DESCRIPTION (Unedited Applicant's Abstract): The development of an ultra-miniature optical pressure sensor is proposed for NHLBI's research topics: Heart and Vascular Diseases, Biosensors. Intended for intravascular use, the sensor must be disposable and, therefore, will be designed to be available at a reasonable cost for clinical use. The small size of the sensor and the flexibility of the optical fibers will result in a pressure transducer, which can be inserted into blood vessels (arteries, veins, or heart chamber) with an angioplasty guide wire with a diameter of only 0.3 mm. The sensor can measure blood pressures in the range of 0 to 300 mmHg with both diastolic and systolic blood pressures. The sensor will operate over time periods of up to a few days without periodic re-calibration. Its pressure readings will be independent of temperature changes in the range of 20 degreesC - 50 degreesC. The primary commercial application of this device will be for angioplasty treatment. Because of its small size, the sensor can be used for infants and also to monitor fluid pressures in the human brain after surgery. The low cost will allow it to be used for small animal research. The Phase I effort demonstrated the feasibility of the proposed approach. Prototype development will be carried out in Phase II. PROPOSED COMMERCIAL APPLICATION: Not Available